Albian infaunal Pholadomyida (Cretaceous Bivalvia), Comanchean Carbonate Shelf, Texas

Species of the Megaorder Poromyata, although common and relatively diverse in Albian-lower Cenomanian Comanchean strata in Texas and northern Mexico, have been neglected as biostratigraphic markers and paleoecological indicators. Since 1852 more than a dozen species have been identified as Homomya Agassiz, Order Pholadomyida, Superfamily Pholadomyoidea, or Pleuromya Agassiz, Order Pholadida, Superfamily Pleuromyoidea. Because valve morphologies of both genera are similar in many ways, casts of both genera are difficult to separate. Statistical analysis of key morphological properties objectively defines species concepts and assesses synonymies. Eight species are retained in Homomya, four are synonymized with these; two species are provisionally retained in “Homomya” although they differ significantly. One species is re-assigned to Liopistha (Sergipemya) alta (Roemer). Pleuromya henselli (Hill) is re-assigned to Panopea.
Homomyid species range from upper Aptian to lower Cenomanian of t...